This addon completely randomizes the sounds in the game, from mob noises, to block noises. This addon is great whether you are attempting a challenge, or if you want to confuse your friends.
This addon is a reasonably large file because it has to have every sound file included.
Every sound effect is randomized, but the music is not. The mobs could have any sound effect such as another mob noise, block walking noise, block-breaking noise, etc. This addon is great to use on your friends or as a challenge.